The present invention relates to a device for the control of blowing air, in particular in a web-fed rotary printing machine or in a turner bar of a web-fed rotary printing machine. The device is connected to a compressed-air source and is formed with at least one outflow orifice, and the device has a valve element which is moveable into a first position in which blowing air flows from the compressed-air source at least through a first duct to the outflow orifice and which is moveable into a second position in which blowing air flows from the compressed-air source at least through a second duct to the outflow orifice. A volume flow through the second duct is thereby greater than a volume flow through the first duct.
The invention relates, furthermore, to a turner bar, in particular for deflecting a printed material web in a web-fed rotary printing machine.
My earlier U.S. Pat. No. 5,797,531 (see German publication DE 196 37 674 A1) discloses a differential-pressure turning-bar arrangement, by means of which a printed material web, for example a paper web, is deflected from a run-in movement direction to a run-out movement direction, the run-out movement direction being determined by the angle of arrangement of the turner bar to the run-in movement direction and by the looping angle of the material web in relation to the turner bar. In order to prevent the printing ink from being deposited from the freshly printed and, where appropriate, dried material web onto the surface, for example the casing, of the turner bar, the turner bar is connected to a compressed-air supply and is provided with air outlet orifices, out of which blowing air is blown into the region between the turning-bar casing and the material web looping around the turner bar. This results, between the material web and the turning-bar casing, in the formation of an air cushion, on which the material web is moved contactlessly over the turning-bar casing, so that a smudging of printing ink on the looped-around surface region of the turner bar is prevented. The turner bar, has, furthermore, inside it, closing elements, with which the air outlet orifices can be partially closed. The closing elements are provided with a bore, through which blowing air can emerge, even when the air outlet orifice is in the closed state, and are moveable in a guide. When an outlet orifice is covered by a material web, the air stream through the bore is obstructed in the closing element, and, as a result of the dynamic pressure which builds up above the closing element, the latter is moved in the guide into a position in which the closing element releases the air outlet orifice. Blowing air can then flow via a bypass from the compressed-air supply to the air outlet orifice and a sufficiently stable and load-bearing air cushion can form under the material web surrounding the turner bar. However, those air outlet orifices of the turner bar which are not covered by the material web continue to remain closed by the closing element, so that only a reduced air stream which flows through the respective bore in the respective closing element passes outward from them.
What is achieved by the arrangement described is that the air outlet orifices not covered by the material web are acted upon only by reduced blowing air. As a result, the compressed-air supply can have, overall, smaller dimensioning. Furthermore, by the blowing air being controlled automatically by means of the closing elements, complicated remotely controllable components and the laborious climbing to the turning-bar superstructure for setting or changing over the blowing-air orifices are unnecessary.
A disadvantage of my older assembly, however, is that it is relatively difficult to mount and maintain and, moreover, that a turning-bar configuration has to be manufactured individually for each predetermined length of the latter. The disadvantages mentioned lead, furthermore, to increased investment and maintenance or repair costs.
It is accordingly an object of the invention to provide a blowing air control device, which overcomes the above-mentioned disadvantages of the heretofore-known devices and methods of this general type. It is a further object of the present invention to provide a turner bar which, while avoiding the above-mentioned disadvantages of the prior art, deflects a material web accurately and without any damage.
With the foregoing and other objects in view there is provided, in accordance with the invention, a device for the control of blowing air, comprising:
a basic body formed with an inlet for connection to a compressed-air source and with at least one outflow orifice;
a valve element moveably disposed between a first position in which blowing air flows from the compressed-air source at least through a first duct to the outflow orifice and a second position in which blowing air flows from the compressed-air source at least through a second duct to the outflow orifice, wherein a volume flow through the second duct is greater than a volume flow through the first duct; and
the basic body being constructed for assembly into a blowing-air body formed of a plurality of the basic bodies.
With the above and other objects in view there is also provided, in accordance with the invention, a turner bar assembly formed with a plurality of modules each including at least one device for the control of blowing air as outlined above and together forming a turner bar. The turner bar is specifically suitable for use in a printing machine, such as a web-fed rotary printing machine.
In other words, a device for the control of blowing air is provided, the device being connected to a compressed-air source and comprising at least one outflow orifice or air outlet orifice, and the device having a valve element which is moveable into a first position in which blowing air flows from the compressed-air source at least through a first duct to the outflow orifice and which is moveable into a second position in which blowing air flows from the compressed-air source at least through a second duct to the outflow orifice, the volume flow through the second duct being greater than the volume flow through the first duct, is distinguished in that the device has a basic body which is designed in such a way that a plurality of such basic bodies can be assembled to form a blowing-air body, in particular a turner bar.
The device according to the invention has, in the first instance, the advantage that it is constructed from two basic elements to be produced or procured cost-effectively, the, for example, essentially disk-shaped valve element and the basic body, so that both the mounting of the device and the subsequent maintenance or repair of the device become possible at low cost and with little labor. There may be provision, moreover, for the basic body to be made multipart and, for example, capable of being assembled.
A further advantage of the device according to the invention arises from the fact that the basic body is designed in such a way that a plurality of such basic bodies can be assembled to form a blowing-air body. It is thereby possible, for example, to construct a turner bar from devices according to the invention with a minimal use of material and minimal labor, as it were in a modular design, and advantageously to provide the required length of the turner bar by the addition or omission of individual devices.
A preferably disk-shaped or flat configuration of the valve element affords the advantage, furthermore, that the, for example, essentially cylindrical basic body can have a small (cylinder) height, so that, with the same predetermined length of, for example, a turner bar, a larger number of devices according to the invention can be assembled to form the turner bar, with the result that the turner bar comprises a larger number of outflow orifices and the sectional control of blowing air with increased spatial definition becomes possible.
Furthermore, the advantage of the prior art that the dimensioning of the compressed-air supply can be reduced is further enhanced by the device according to the invention, since, due to the use of the above-described basic bodies, the construction of the blowing-air bodies varies and can be adapted to the prevailing requirements of the material-web transport.
It is also possible, furthermore, to make the valve element deformable and to deform the valve element from the first position to the second position, and vice versa.
In a further embodiment of the present invention, the valve element may advantageously be designed as a diaphragm valve, plate valve or disk valve. It is possible, for example, to manufacture the diaphragm valve preferably from an elastomeric material or an elastomeric mixture, a disk, for example a plastic or metal disk, being capable of being embedded into the elastomer or of being applied or adhesively bonded to the elastomer. It is possible, moreover, for the diaphragm valve to have an airtight edge region which is designed as a concertina and can be received, for example, in a groove of the basic body.
In a further version according to the invention of the device, there may be provision for the basic body to have a first chamber with a seat for the valve element, the chamber being connected to the outflow orifice by means of the first duct, and for the valve element to be moved into the second position when the air pressure in the first chamber is increased and to be moved automatically into the first position when the air pressure in the first chamber is reduced. It is also conceivable for the basic body to have a second chamber which is connected to the atmosphere by means of a third duct in such a way that an unimpeded movement of the valve element becomes possible by pressure equalization.
It may be remarked here, that the term xe2x80x9cchamberxe2x80x9d designates any kind of recess or space in the basic body, even when the chamber is not closed off by walls on all sides. Thus, for example, there may be provision for the first and the second chamber each to be open on one side, to adjoin one another in each case with this open side and to be separated from one another on this side by the valve element, for example, the diaphragm valve.
It may also be remarked, here, that the term xe2x80x9cductxe2x80x9d designates any connection made in the basic body, for example between orifices of the basic body, chambers formed in the basic body or the outflow orifice and a chamber, while a duct may also be open with one longitudinal side, for example, to a chamber.
It is also possible, furthermore, to design the ducts as lines, in which case, for example, hoses, in particular rubber hoses or tubes, may be provided.
It is also possible for the basic body to be of essentially cylindrical or disk-shaped design, the at least one outflow orifice being arranged in the edge region of the cylinder or of the disk, and for the disk-shaped valve element to be oriented preferably essentially parallel to the basic body.
This special type of arrangement of the basic body and disk-shaped valve element advantageously makes it possible to provide a device with a very small construction height and thereby assemble a large number of such devices, which may also be designated as modules or members, to form a turner bar of predetermined length.
In a further refinement of the device according to the invention, the basic body may have, on one side, a centering and, on another, opposite side, a receptacle for a centering of a further basic body.
What is advantageously achieved thereby is that the individual basic bodies can be assembled accurately and simply.
Furthermore, the basic body may have a compressed-air entry on one side and a compressed-air exit on another side, the compressed-air exit being connected to the compressed-air entry of the basic body, and the compressed-air exit being capable of being connected to, in particular plugged together with, the compressed-air entry of a further basic body.
By virtue of this special type of construction of the basic body, the basic body of a device can advantageously be connected to the compressed-air source, for example via a hose line, while the further basic bodies are not connected directly to the compressed-air source, but are supplied with compressed air by the basic body in each case arranged adjacently in the direction of the compressed-air source. The individual basic bodies lined up directly or indirectly with one another thus advantageously form a compressed-air line.
In a further embodiment of the invention, there may be provision, during the movement of the valve element, for a plurality of ducts to be released, for example in succession, in which case the volume flow through these ducts may be in any desired relation to the volume flow through the first duct, so that the overall volume flow is greater than the volume flow through the first duct.
A turner bar according to the invention, in particular for deflecting a printed material web in a web-fed rotary printing machine, is distinguished in that the turner bar is constructed at least partially from modules, in particular from structurally identical modules, which each comprise at least one device of the type described above.
Turner bars according to the invention of modular or membered design can be manufactured simply and cost-effectively and, furthermore, advantageously have length and construction variability. A variable construction of one or more turner bars can be achieved, according to the invention, in that differently configured turning-bar modules or turning-bar members are used for constructing the turner bars. It is also conceivable, furthermore, to insert between the individual modules intermediate members which do not have a device for the control of blowing air and, for example, serve merely as spacers between individual devices according to the invention and transfer the blowing air from one device to the next. Moreover, the basic bodies of the individual modules, the basic bodies also being capable of constituting the modules themselves, may have a variable height and also a variable number of air outlet orifices.
In a further refinement of the invention, a turner bar may comprise a plurality of air outflow orifices arranged essentially parallel to the longitudinal axis of the turner bar. Those air outflow orifices which are covered by a material web are in this case acted upon by a large volume flow of blowing air by means of a respective device for the control of blowing air, whereas those air outflow orifices which are not covered by a material web are acted upon by a small volume flow of blowing air from the respective device for the control of blowing air.
It is possible, moreover, for the modules of a turner bar according to the invention to be surrounded at least partially by a turning-bar casing which may have casing holes which are in alignment with the air outflow orifices of the modules.
The turning-bar casing can thus advantageously stabilize the lined-up modules and, for example, be manufactured from a material which additionally prevents printing ink from being deposited on the surface of the turner bar and/or is easy to clean.
A printing machine according to the invention, in particular a web-fed rotary printing machine, a folder according to the invention or a folder superstructure according to the invention are distinguished by a device or a turner bar of the type described above.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a device for the control of blowing air, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.